Vulcanizing-press



Patented Apr. 25, |899.' L. K. SCOTFORD.

VULCANIZING PRESS.

(Application med Feb. 10, 1898.)

2 Sheets-Sheet l.

(No Model.)

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Patented Apr. 25, |899.

L. K. SCOTFURD.

VULCANZING PRESS.

(Application led Feb. 10, 1898.)

2 Sheets-Sheet 2.

(No Model.)

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LOUIS K. SCOTFORD, OF CHICAGO, ILLTNOIS.

VU LCANIZING-PRESS.

SPECIFICATION fOlmllg part Of Lettel' Patent NO. 623,838, dated pll 2 5, 1899.

Application tiled February 10, 1898- Serial No. 669,755. (No model.)

To all whom t may concern:

Be it known that l, LOUIS K. SOOTFORD, ofV

Chicago, in the county of Cool: and State of Illinois, have invented certain new and useful Improvements in Vulcanizing-Presses; and Il being had to the accom pauyiug drawings, andto the letters of reference marked thereon, which form a part of this specification.

This invention relates to an improved apparatus for use in vulcanized articles of rubber-such, for instance, as rubber type-sheets used inhand-stamps.

The invention relates more particularly to an apparatus of that class in which the article to be vulcanized is subjected to' direct pressure of opposin g surfaces and at the saine time subjected to the action of heat communicated thereto from said opposing surfaces, said apparatus being in this respect like that shown in my prior patent,No.407,255, granted July 1G, 1889.

The invention consists in the matters here-V inafter setforth, and more particularly pointed out in the appended claims.

In the drawings, Figure l is a front elevation of an apparatus constructed in accordance with my `invention.V Fig. 2 is a side elevation thereof. Fig. 3 is avertical section taken on line 3 3 of Fig. 1. Fig. 4 is a detailed section taken on line 4 4 of Fig. 2. Fig. 5 is a detail section taken on line 5 5 of Fig. 2.

As shown in said drawings, A designates the lower part or platen of the press, which is supported upon legs or standards B, and C designates the upper part or follower thereof. Said platen consists of a hollow casting,which is herein shown as of rectangular shape, as seen in plan view, at the upper part thereof. Said hollow platen is provided in its lower part with a cylindric cup-shaped water-receptacle A', forming a steam-generator,and is closed at its upper part 'by a flat horizontal wall A2, which constitutes the su pportin g-surface of the platen, between which and the follower the rubber is compressed. Said platen is provided at its opposite sides, in the upper part thereof, with upwardly-extending side pieces or tianges A3 A3, which form the sides of a chamber C', in which the follower C is located and of which the supportingsurface of the platen forms the bottom or floor. Said chamber is closed at its upper end by means of a plate or wall A4,which is secured in place by means of tap-bolts a a, passing through the margins thereof and into the upper edges of the side walls A3. The rear wall of said chamber is formed by a depending flange A, secured upon or formed integral with the rear end of the plate A4, and said rear wall rests when said plate is in place between the side walls A3. The said chamber C4 is without any front wall and is provided at its front part with an opening A7, through which the matrix and the rubber to be vulcanized may be inserted into and removed from said chamb er. Said u pper wail A4 is provided centrally with a' hub A6, through which passes a screwshaft C2, which bears at its inner end upon the top of the follower C and is provided with a hand-wheel C3. Said plate or wall A4 is provided in the corners thereof with set-screws a a', which are adapted to be screwed down upon the follower C to hold the latter in contact with the rubber to be vulcanized independently of the central shaft C2, by which latter said follower is raised and lowered.

The follower C is preferably made to fit closely within the air-chamber C and is sustained in a position parallel with the supporting-surface A2 of the hollow platen by the shaft C2. In order to afford the necessary stiffness or rigidity to the said follower to prevent it from bending under the strain coming thereon when the form is clamped between the platen and follower, the latter is provided with a centrally-arran ged hub or boss C4,which extends above t-he plate forming the follower, preferably convex in form, and with the top of which the screw-threaded shaft C2 is engaged. Anyotherconstructionin thefollower to give stiffness thereto may be used, however, as found most convenient or desirable. The upper wall A4 of the hot-air chamber C' is bulged outwardly to form in its inner surface a concave recess adapted to receive the portion C4 of the follower when the latter is moved away from the platen A. Such construction of the wall A4 also serves to provide greater strength and rigidity in the same to resist the upward thrust of the shaft C2 when the follower C is screwed down upon the platen A.

IOO

The platen A is provided exteriorly above the water-receptacle with an offset portion or recess a2, within which the upper ends of the standards or legs B rest and by which the wtid platen is supported. That part of the hollow platen between the water-receptacle A' and the upper supporting wall or surface A2 thereof constitutes a steam-chamber, into which the steam vpasses from the water-receptacle.

a3 designates a water-feed pipe which opens into the interior of the platen above the waterreceptacle, and a a water-pipe by which the water in the receptacle may be maintained to a predetermined height.

uf designates a pressure-gage connected with the hollow platen by a pipe a, and al a safety-valve connected with the interior of the platen. 'lhe pressure-gage affords a convenient means for determining the pressure of the steam, and thereby regulating the temperature of the pressing-surfaces.

The water-receptacle A may be heated in any preferred manner. As herein shown, a gas-burner D is located upon a supportingplate E beneath said receptacle, said burner being supplied with fuel through the medium of a pipe D'. As a means for preventing the llame of the burner from being deflected by drafts of air and also to retain the heat under the water-receptacle a jacket or shield E of sheet metal is placed around the burner, said shield extending upwardly to within va short distance of said water-receptacle at the line of its greatest diameter. Asa preferred construction thc side walls of said jacket E are connected with the supporting-plate E, and said jacket and plate are held in position by means of bolts b, which are tapped through the legs or standards ll and upon the inner ends of which said plate and jacket are sustained. Said standards will desirably be provided with marginal longitudinally-extending flanges b, which form guides to engage the adjacent corners -of the jacket and by which said jacket is held from lateral movement. Said jacket is provided in one of its outer walls with a port or opening E2, through which the flame is visible from the outside thereof, and is provided in the horizontal part E with air-inlet openings e e, through which air enters to reach the burner D.

Steam will be generated in the hollow platen A to a predetermined pressure, when it will escape through the safety-valve a7, by means of which the pressure of the steam within said platen and the temperature of the pressing-surfaces can be controlled. The movable follower C is not directly connected with the steam-chamber of the hollow platen, as in the construction of my said prior patent; but said movable follower or upper pressing-plate is heated by heat transmitted from the steam within the hollow platen, through the sup` porting or pressing surface A2 of the hollow platen, to the air within the chamber C and also to some extent through the side walls of the chamber and the mold between the platen and follower when said mold is clamped between the same.

I have found by experiment that the pressing-surfaces of the follower and platen made as described lnay be maintained at a practicall y equal temperature and that the results obtained are substantially as goed as in the construction wherein the movable follower is made hollow and is connected with the hollow platen in -whieh the steam is generated by connecting-pipes, as in the construction of my said prior patent.

In the use of the apparatus described for makinga rubber printing-sheet a mold or matrix having the reverse of the types or printing characters desired is placed upon the platen with the sheet of rubber, prepared in readiness for the application of heating-pressure, in contact with the same. The follower is then brought against the rubber to force the same into contact with all the parts of the matrix. After the follower has been forced against the rubber by the use of the hand-wheel C3 the set-screws a' of the upper wall A4 of the chamber C are then forced down against the follower` by the use ofasuitable tool, so that said follower is held rigidly in place while the process of vulcanizing is taking place without reliance upon the shaft C2 for giving pressure, said shaft being used mainly for the purpose of lifting and lowering the follower. The set-screws may also be used for the purpose of forcing down the follower with greater pressure than can be exerted by the use of the hand-wheel alone. In order to prevent the central screw-shaft from interfering with the action of the setscrews a when said screws are moved downwardly against the follower, said follower has a freedom of vertical movement to a limited extent with relation to the upper wall A4 of the air-chamber C. Such freedom of movement may be provided either between the shaft and said upper wall or between the shaft and the follower. The latter arrangement is herein shown and is made as follows: The shaft is provided at its inner end with an outwardly-extending flange c, which fits within a socket on said follower, herein shown as consisting of a detachable apertured block c, secured tothe follower by bolts in the manner shown. Said block is provided with a radially inwardly extending flange c2, which overlaps the flange c of the shaft and prevents the same from becoming detached therefrom. The depth of the socket inside the flange c2 is greater than the width of the flange c, so that in the upward movement of the shaft the flange c will engage the flange c2 and in the downward movement thereof it will engage the upper surface of the follower, thereby affording lost motion between the shaft and follower sullicient to permit the set-screws to advance the follower to a necessary extent after it has been carried against the work by the screw-shaft.

IOO

IIO

As a further improvement in apparatus of the class described the hot-air chamber C' is provided with a removable or sliding drawer which receives the matrix and which is inserted into and removed from the chamber through the opening A7 at the front wall thereof. Said drawer consists of a iiat plate G, which when in place rests upon the supporting-surface A? of the hollow platen and is of such size as to entirely cover the same. To the forward end of said plate is attached an u pwardly-extending plate or flange G', which is ol' such size as to'overlap thei margins of and entirely cover the opening A7 of the chamber C' and which forms when in place the front wall of the said chamber. The plate or flange G' is provided with a handle Gr2 by which the drawer may be manipulated.

As a convenient construction the apparatus will be provided with a shelf or ledge A8, which forms an extension of the Supporting-surface Agof the hollow platen at the front part thereof and whichis adapted to receive the drawer when it is withdrawn from the hot-air chamber C. As a further improvement and in order to prevent the drawer from being accidentally moved oif the shelf when withdrawn from the chamber C said drawer is provided on its opposite side thereof with depending guide-lugs g g, which engage the opposite margins of the shelf to prevent lateral movement of the drawer upon said shelf. Said shelf is also provided in its outer end with stop-pins g g', which limit the outward movement of the drawer thereon.

The matrix employed for giving shape to the articles of rubber, such as rubber typesheets, are made of a compound containing plaster and other ingredients and which requires heating or baking to harden the same preparatoryr to the application of the rubber sheets thereto, the means provided in my said prior construction for so hardening or baking the matrix consisting of a hot-air chamber or oven provided especially for that purpose and located above the movable follower, so that it was necessary to remove said matrix after being dried or hardened in said air-chamber and place the same between the platen and the follower after the rubber sheet had been applied thereto. In the present construction the matrix will be heated to harden the same by placing it within the hotair chamber C beneath the follower when the same is lifted to give room for the matrix. In practice the matrix will first be placed on the bottom plate of the drawer and the latter then thrust into the hot-air chamber and allowed to there remain until properly dried or hardened. The drawer will then be pulled out and the rubber sheet applied to the matrix. The drawer will then again be thrust in and the follower forced down upon the rubber sheet and matrix to press or squeeze the same together. The parts will be allowed to remain in this condition until the rubber has been acted upon by the heat long enough to 'produce proper v'ulcanization thereof. rlhe operation of drying the matrix and vulcanizing is thereby much simplified.

The main feature of my invention is comprised in the construction in which the movable follower and supporting-surface of the hollow platen are contained within a chamber which forms an inclosure adjacent to the heated surface of said hollow platen to receive heat from the heating medium thereof, but which itself is not provided with heating means. This engagement simplifies the construction of the apparatus by obviating the necessity of providing connections through which a heating medium, such as steam, may be transmitted to the follower which connections are required to be made flexible to permit movement of said follower and which are expensive to construct and require constant attention to prevent escape of the heating medium therefrom.

Another important feature of my invention which arises from the fact that the heating medium is not introduced directly to the follower or the chamber containing the same is that the chamber which is used to aid in the application of heat to the rubber sheet while pressure is being applied thereto in the process of vuleanizing may be used for drying the matrix. The construction by which this result is obtained is not only much simpler than the prior constructions and cheaper to manufacture, but also greatly simplifies the operation of drying the matrices and afterward applyin g thereto the rubber sheets to be vulcanized. Moreover, such construction enables the apparatus to be made of more compact form and to occupy less space in a factory than the prior constructions, containingin one machine the drying and heating devices.

A further practical advantage gained by the use of the construction described is that the follower is contained entirely within the hot-air chamber, the upper wall of said chamber serving as a yoke with which the'screwthreaded shaft of the follower is engaged. Such construction affords great compactness, while the 4apparatus occupies a minimum of Space and is at the same time more economical to manufacture. v

For the general purpose of my invention the water-receptacle need notbe located as herein illustrated, but steam may be supplied to the hollow platen from any suitable source or means of steam-supply. Moreover, it is obvious that the hollow platen may be placed above the hot-air chamber and the arrangement of the parts reversed, so that the follower will move upwardly against the platen. The arrangement herein illustrated,however, is a desirable one in point of simplicity an convenience, and is therefore made the subject of speciic claims herein.

I claim as my inventionl. An apparatus for the purpose set forth, comprising a hollow stationary platen pro ICO IIO

vided with a water-reeeplaele in connection with the interior thereof and forming a steamgenerator, a movable follower, and a chamber inclosiirgY the follower.

2. The combination with a platen, a follower movable toward and from the platen, a chamber containing the follower, a screwthreaded shaftengagingthe wall ofsaid chamber and acting,r upon said follower, a plurality of set-screws having screw-threaded engagement with the said wall of the chamber and acting upon said follower, said parts being constructed to afford lost motion between said follower and the wall of the chamber.

The combination with a platen, a follower movable toward and from the platen, a plate supported above said follower and a screw-threaded shaft engagingT said plate and acting upon the follower, of a plurality of bolts having screw-threaded engagement with the plate and acting upon said follower, said shaft being,r connected with the follower by means affording lost motion between the same.

i. The combination'with a platen havinga horizontal supporting-surface, a follower, top and side walls forming a chamber which su rrounds the follower and is provided with an opening in one of its side walls, a drawer adapted to be vinserted into said chamber through said opening, and a shelf havingits upper surface iu the same plane with the supporting-surface of the platen and adapted lo receive said drawer when the latter is withdrawn from the chamber.

5. The combination with a platen havinga horizontal supporting-surfaee, a follower, top and side walls forming a chamber which incloses the follower and which is provided with an opening in one of its side walls, a drawer adapted to be inserted into said chamber through said opening, and a shelf having its upper surface in the same plane with the snpporting-surfaee of the platen, and adapted to receive said drawer when the latter is withdrawn from the chamber, said drawer beingr provided with guide-lugs which engage guidesurfaees on the shelf.'

G. An apparatus for the purpose set forth comprisingahollowstationaryplaten,aeham ber located above said platen, the bottom Iloor of which is formed by the upper wall of the platen, a follower in said chamber movable toward and from said platen and a sliding drawer in said chamber, the outer part of which forms one of the walls of the chamber.

In testimony that I claim the foregoing as my invention I affix my signature, in presence of two witnesses, this 8th day of February, A. l). 1898.

LUIS K. SCOTFORD.

Witnesses:

'lAYLon E. BROWN, W. A. WHrrEHnAD. 

